Transplantation of cultured human adrenal chromaffin cells into 6-hydroxydopamine-lesioned rat brain

Adult young rats were subjected to a unilateral 6‐hydroxydopamine lesion of the nigrostriatal dopamine pathway and then given intrastriatal grafts of human fetal adrenal chromaffin cell cultures. Amphetamine‐induced ipsiversive turning behavior in the lesioned rats was largely reversed in four of eight rats given such transplants when tested at 1.5 and 4.5 months post‐transplantation. Two rats showed a transient recovery at 1.5 months followed by deterioration at 4.5 months, while two other rats showed continuous deterioration. Six rats given sciatic nerve grafts as controls all showed deterioration from the pretransplantation levels. Catecholamine fluorescent and immunohistochemical examination of chromaffin‐cell‐transplanted brains demonstrated neurons and neuronal processes positive for catecholamines or tyrosine hydroxylase in the transplanted area. This transplantation of cultured human fetal cells to an animal model may provide the necessary basic experimental system for assessing the possible utility of human neuronal transplants.